Substance abuse among homeless youth is twice that of school youth. Runaway youth also report a broader range and higher severity of substance-related, mental health and family problems relative to school youth. Shelters for runaways are overcrowded, and most shelters focus exclusively on crisis intervention, and are therefore not equipped to treat youth for drug, alcohol, family and related problems. To date, few studies have examined treatment effectiveness with this population. Given the high level of risk for health and psychological problems and their associated long-term social costs, there is a great need for identifying potent interventions. The PI examined the effectiveness of Ecologically-Based Family Therapy (EBFT) with substance abusing runaway youth in runaway shelters, through a Stage I FIRST award trial. To our knowledge, this is the first systematic evaluation of a substance use and mental health treatment with this population. The proposed study is a Stage II clinical trial examining outcome for three theoretically distinct interventions that have empirical bases: Community Reinforcement Approach, Motivational Interviewing and EBFT. The relative effectiveness and therapeutic change process of the proposed interventions for runaway youth will be evaluated 3, 6, 9, 12, 18 and 24 months after treatment, and will include measures of substance use, family relations, and adolescent functioning. Study aims also will investigate how, if at all, treatment compliance and satisfaction mediate youth response to the three treatments. This project will also evaluate the cost-savings potential associated with each treatment intervention.